: An atomic force microscope (AFM) that quantitatively measures the force on the tip when near the surface and uses the measurement to compute contact and reverse direction of cantilever base and tip has been designed and built. The "Sensing Mode" method characterizes the surface structure of sensitive biological macromolecules such as soluble protein with much reduced damage compared to contact mode. The specific aim of Phase I research is to construct a marketing prototype and to carry out demonstration experiments using the prototype. Data will be taken in mother liquor on the surface topography of protein crystals and in reaction buffer on single-copy protein structures assembled on DNA. Low damage will be demonstrated by sequential scans of the same area and biological function shown by observing crystal growth in the first kind of experiment and interpretable protein motion or conformational change in the second. PROPOSED COMMERCIAL APPLICATION: NOT AVAILABLE